The container executor configuration reader does not handle white spaces or malformed key value pairs in the config file correctly or gracefully
as an example the following key value line which is part of the configuration (note the << is used as a marker to show the extra trailing space):
is a valid line but when you run the check over the file:
Can't get group information for yarn - Success.
It fails to find the yarn group but it really tries to find the "yarn " group which fails. There is no trimming anywhere while processing the lines. If a space would be added in before or after the = sign a failure would also occur.
Minor nit is the fact that a failure still is logged as a Success